1. Field of the Invention
The present invention relates to a clutch control hydraulic circuit for a vehicle or the like. More particularly, the present invention relates to such a clutch control hydraulic circuit which can be automatically and manually operated, and which reliably controls connection and disconnection of a clutch device under both normal operation and fail safe operation.
2. Background Art
As a conventional clutch control hydraulic circuit, and a method for assigning an electronically-controlled automatic connection and disconnection function, and a manually-controlled manual connection and disconnection function to a common clutch device, Japanese Patent Application Publication No. Hei 8-296670 discloses that hydraulic circuits associated with a clutch pedal and motor are unified by inserting a three port valve in between these components.
Japanese Utility Model Registration Application Publication No. Hei 5-014664 discloses another known clutch apparatus for a vehicle and, more particularly, such a clutch device which automatically performs the opening operation of the clutch independently of the clutch pedal.